Another dimension, other than orbit, that might be possible to adjust, in order to avoid a space object is the ecliptic. The ecliptic is the plane on which the earth travels as it orbits the Sun. For full explanation see:
http://www-spof.gsfc.nasa.gov/stargaze/Secliptc.htm
Our interest in the ecliptic is the possibility that we may keep the orbit the same, but change the plane slightly if that were found to be of value in dodging space objects. For some interesting diagrams showing the ecliptic in relation to comets, see: